In 2004, a 13-year-old boy experienced an injury that left him blind. The front of his eyes were damaged by a rare medical condition. His optic nerve and the back of his eyes were healthy, but no light could reach them through his damaged corneas, the clear part at the front of the eye. Through the years, doctors tried transplanting corneas from donors over and over, but all the transplants failed.
Then, over 20 years later, his doctors proposed an unusual treatment. If successful, the procedure would allow him to see again. There was a catch, though. The patient had to use another part of his body in the procedure to restore his vision.
What body part did the surgeons require? A tooth. Where did they plan to put this tooth? Into his eye! 😮
Osteo-odonto-keratoprosthesis, also known as "tooth-in-eye" surgery, is very real, but it sounds like science fiction from start to finish.
First, doctors have to create a smooth, healthy surface across the front of the eye. They do this by using another part of the patient's body - the lining from part of the inner cheek. The doctors remove the damaged eye tissue and cover the front of the eye with the cheek lining.
Doctors then take the pulled tooth and shape a piece of it into a curved rectangle that can fit across the front of the eye. The rectangle of tooth material is strong enough to be drilled and hold a small plastic tube that has a lens inside. When the piece of tooth is implanted into the eye, the lens allows light to pass through to the back of the eye so the patient can see again!
This wild procedure has another strange twist: the tooth can't go straight from mouth to eye. First, the tooth must be prepared to connect to the eye tissue. Doctors do this by taking the tooth and embedding it into the patient's cheek for a few months. While the tooth is in the cheek, connective tissue starts to grow on it. The tissue gives surgeons connection points to attach the tooth to the eye.
Why use a tooth? Doctors need a material strong enough to hold the plastic tube, but our eyes are sensitive and will try to reject any strange materials placed inside them. Sometimes our bodies will also reject organs and tissue from other donors. With the tooth-in-eye surgery, doctors avoid both these problems by using parts from the patient's own body.
What might be the wildest part of this procedure is that it was developed in the 1960s! It was modified through the years until, in the 1990s, it reached the process that basically still works today. Many patients can see well enough to drive, and some have 20/20 vision!
Even though it has been around for decades, tooth-in-eye surgery is not very common. Only about 800 people worldwide have been through it. Corneal transplant is faster, easier, and gives better results, so most patients with damaged corneas will go through corneal transplant instead. The graph below shows the number of cornea transplant surgeries in Australia over the last few decades:
If I brought this graph to my students, here are some questions I would ask:
💡What does the y-axis, or dependent variable, from the graph tell us? What does the x-axis, or independent variable, tell us?
💡What are two patterns that you observe in the data presented on the graph?
💡What is the approximate total number of surgeries that happened in the years from 1995 to 2000? How does this number compare to the total number of tooth-in-eye surgeries mentioned in the article?
